采用加速高分辨率质子磁共振波谱成像技术在 3T 和 7T 下绘制扩展神经化学图谱。

Mapping an Extended Neurochemical Profile at 3 and 7 T Using Accelerated High-Resolution Proton Magnetic Resonance Spectroscopic Imaging.

机构信息

From the *High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna; and †Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria.

出版信息

Invest Radiol. 2017 Oct;52(10):631-639. doi: 10.1097/RLI.0000000000000379.

DOI:10.1097/RLI.0000000000000379

PMID:28459799

Abstract

OBJECTIVES

The aim of this study was to compare high-resolution free induction decay magnetic resonance spectroscopic imaging (FID-MRSI) at 3 T and 7 T in the brain of healthy subjects and to showcase the clinical potential of accelerated FID-MRSI at 7 T in 2 brain tumor cases.

MATERIALS AND METHODS

In this institutional review board-approved study, 10 healthy volunteers (8 men/2 women; age: 31 ± 6 years) were measured at 3 T and 7 T (Trio and 7T-Magnetom; Siemens Healthcare, Germany) and 2 patients (a 38-year-old man and a 37-year-old man), 1 with an anaplastic oligoastrocytoma (grade III) and 1 with a low-grade glioma (oligodendroglioma), were measured at 7 T.Free induction decay MR spectroscopic imaging with 3.4 × 3.4 mm in-plane resolution was acquired in 30 minutes/6 minutes (nonaccelerated/accelerated) at both field strengths. In addition, single-slice or multi-slice FID-MRSI at 7 T was measured in the 2 tumor patients at 7 T within 6 minutes/13.3 minutes. Signal-to-noise ratio, Cramer-Rao lower bounds, and parallel imaging efficiency were assessed. High-resolution maps were created for 9 different brain metabolites.

RESULTS

At 7 T, 7 of 9 metabolites were reliably mapped over the whole slice but only 3 at 3 T. Parallel imaging efficiency was significantly improved at 7 T. Signal-to-noise ratios were +75%/+66% (P < 0.05) for N-acetylaspartate and +97%/+74%(P < 0.05) for glutamine + glutamate [Glx], and full-widths at half maximum were +112%/+109%(P < 0.05) higher at 7 T than at 3 T (nonaccelerated/accelerated) for N-acetylaspartate. Cramer-Rao lower bounds were more than double at 3 T (P < 0.05).

CONCLUSIONS

At 7 T, FID-MRSI allowed the assessment of an extended neurochemical profile and yielded better metabolic maps in only approximately 6 minutes at 7 T than in approximately 30 minutes at 3 T. We found several potentially therapy-relevant neurochemical alterations in brain tumors that highlighted the potential of fast clinical FID-MRSI at 7 T.

摘要

目的

本研究旨在比较健康受试者在 3T 和 7T 下高分辨率自由感应衰减磁共振波谱成像（FID-MRSI），并展示在 7T 下加速 FID-MRSI 在 2 例脑肿瘤病例中的临床应用潜力。

材料与方法

在本机构审查委员会批准的研究中，10 名健康志愿者（8 名男性/2 名女性；年龄：31±6 岁）在 3T 和 7T（Trio 和 7T-Magnetom；西门子医疗，德国）进行测量，2 名患者（1 名间变性少突胶质细胞瘤患者[III 级]和 1 名低级别胶质瘤患者[少突胶质细胞瘤]）在 7T 下进行测量。在两种场强下，使用 3.4×3.4mm 平面分辨率采集 30 分钟/6 分钟（非加速/加速）的自由感应衰减磁共振波谱成像。此外，在 2 例肿瘤患者中，在 7T 下使用单/多切片 FID-MRSI 在 7T 下测量 6 分钟/13.3 分钟。评估了信噪比、克拉默-罗下限和并行成像效率。对 9 种不同的脑代谢物进行了高分辨率图谱的绘制。

结果

在 7T 下，9 种代谢物中的 7 种在整个切片上可靠地进行了映射，但在 3T 下只有 3 种。7T 下的并行成像效率显著提高。与 3T（非加速/加速）相比，N-乙酰天冬氨酸的信噪比分别提高了+75%/+66%（P<0.05），谷氨酸+谷氨酰胺[Glx]的信噪比提高了+97%/+74%（P<0.05），N-乙酰天冬氨酸的半峰全宽提高了+112%/+109%（P<0.05）。克拉默-罗下限在 3T 时增加了一倍以上（P<0.05）。